Quantum Theory of Exciton Magnetic Moment: Interaction and Topological Effects
Abstract
Combining magnetometry with optical spectroscopy has uncovered novel quantum phenomena and is emerging as a platform for quantum information science. Yet, the theory of magnetic response of excitons, correlated electron-hole pairs in semiconductors, remains incomplete due to insufficient treatment of electron-hole interaction and topological effects. In biased bilayer graphene, for instance, theoretical predictions of valley g-factor for p-excitons deviate from experiment by nearly an order of magnitude. Here, we develop a quantum theory of exciton orbital magnetic moment that reveals several conceptually new terms absent in prior theories, including an unforeseen contribution from exciton band quantum geometry. Our ab initio calculations yield results in excellent agreement with measurements, establishing the importance of a full theory including interaction and topological effects for the magnetic response of excitons.
Keywords
Cite
@article{arxiv.2509.07284,
title = {Quantum Theory of Exciton Magnetic Moment: Interaction and Topological Effects},
author = {Gurjyot Sethi and Jiawei Ruan and Fang Zhang and Weichen Tang and Chen Hu and Mit Naik and Steven G. Louie},
journal= {arXiv preprint arXiv:2509.07284},
year = {2025}
}